Silver halide emulsion containing a stabilizing combination of a 4-hydroxy tetrazaindene and a mono-basically sulfated vinyl copolymer

ABSTRACT

Photographic silver halide emulsions containing speed addenda may be stabilized by a fog-inhibiting combination comprising an azaindene and a monobasically sulfated vinyl copolymer.

United States Patent [191 Abel [451 Dec. 18,1973

[75] Inventor: Edward P. Abel, Webster, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Mar. 6, I972 [21] Appl. No.: 232,195

[52] US. Cl 96/76 R, 96/l07, 96/109 [51] Int. Cl. G03c 1/28, G03c 1/34, G03c 1/48 [58] Field of Search 96/l09, 107, 76 R [5 6] References Cited UNITED STATES PATENTS 3,449,126 6/1969 Minsk 96/l09 3,437,486 4/1969 King et al. 96/109 3,039,873 6/1962 Beavers 96/107 Primary Examiner-Norman G. Torchin Assistant Examiner-Won H. Louie, Jr. Attorney-R0bert W. Hampton et al.

[57] ABSTRACT Photographic silver halide emulsions containing speed addenda may be stabilized by a fog-inhibiting combination comprising an azaindene and a monobasically sulfated vinyl copolymer.

15 Claims, No Drawings SILVER HALIDE EMULSION CONTAINING A STABILIZING (IQMBINATION .QFA arra on BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a new and useful combination of antifoggants and stabilizers for sensitized photographic elements, and to photographic silver halide emulsions containing said antifoggants and stabilizers.

2. DESCRIPTION OF THE PRIOR ART During development of a silver halide emulsion, small amounts of silver halide are reduced to metallic silver regardless of whether or not they have been exposed. This reduction of silver ion produces a background fog which is more specifically referred to as chemical fog.

Chemical fog, apparent in most silver halide systems, can be reduced by prior art methods of processing exposed silver halide material in the presence of compounds which restrict development of unexposed silver halide. Such compounds can be incorporated in the silver halide emulsion or in the processing solutions for developing such silver halide emulsions. Compounds which have been found to have a chemical fog inhibiting effect on emulsions which have been subjected to high temperatures and high humidity conditions are referred to as emulsion stabilizers. On the other hand, compounds which have been found to have fog inhibiting effects on emulsions which have not been exposed to adverse storage conditions are referred to as antifoggants. Although a large number of emulsion stabilizers and antifoggants have been used in the prior art, many of these compounds cause undesirable losses in emulsion speed and contrast, and others lack adequate compatibilty with emulsion gelatin. This is particularly true in emulsions containing such speed addenda as polyonium compounds, alkylene oxide polymers or thioether polymers.

The use of such speed addenda or development accelerators is well known. Unfortunately, many of the polymeric compounds of this type that have been found to give an excellent speed increase are accompanied by a high level of fog that makes their use impractical.

There are a number of teachings in the prior art pertaining to such speed addenda as onium compounds, alkylene oxidepolymers and thioether polymers, and anti-foggants useful for photographic emulsions sensitized therewith. For example, U.S. Pat. Nos. 2,866,437 and 3,017,271 describe photographic emulsions sensitized with alkylene oxide polymers and quaternary ammonium salts and compounds, containing as a preferred antifoggant, an azaindene. In addition, U.S. Pat. No. 2,716,062 describes the use of tetrazaindene stabilizers for emulsions sensitized with alkylene oxide polymer; while U.S. Pat. No. 2,784,091 describes the use of a tetrazaindene stabilizer for emulsions sensitized with polyalkylene esters, amides and ethers.

However, the prior art has not fully overcome the fog problem without causing a significant loss in attainable speed. Thus, while it is known that large speed increases are available through the use of speed addenda, such speed increases have been accompanied by uncontrolled fog. The use of known antifoggants, such as tetrazaindenes, has alleviated the stability problem to some degree, but at the expense of speed.

Hence, it is an object of this invention to provide a new and effective antifoggant combination for use in silver halide photographic emulsions. It is another object of this invention to provide photographic emul sions and elements having high speed and good stability.

It is a further object of this invention to provide photographic elements employing speed addenda, wherein fog formation is controlled. And, it is an object of this invention to provide photographic silver halide emulsions and elements comprising speed addenda and an antifoggant combination comprising an azaindene and a sulfated vinyl copolymer.

SUMMARY OF THE INVENTION This invention relates to the use of a combination of antifoggants which stabilize photographic silver halide emulsions containing speed addenda.

It has been found that excellent photographic stability may be obtained by the use of a combination of azaindene and copoly(vinyl alcohol-vinyl sulfate) antifoggants in silver halide emulsions containing onium compounds, such as quaternary ammonium salts, as speed addenda. In addition, it has been found that emulsions utilizing alkylene oxides, such as polyalkylene glycols, or thioether polymers as speed addenda may be effectively stabilized by this combination of antifoggants.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is well known that silver halide emulsions may be chemically sensitized with a variety of materials in order to increase the speed and generally the gamma of the emulsion, as opposed to optical or spectral sensitization in which the optical range of sensitivity is increased. Chemical sensitization usually results either from the formation of silver sulfide on the surface of the silver halide crystal, thus increasing sensitivity, or from the formation of small amounts of silver from the reduction of silver halide. Other classes of compounds such as certain ethylene oxide condensation products and certain cationic surface-active salts increase sensitivity of silver halides without apparently entering into chemical combination with the silver halide.

Among the onium compounds suitable for use as speed addenda are quaternary ammonium salts, quaternary phosphonium salts, and ternary sulfonium salts. Onium compounds suitable for use in this invention are disclosed in Carroll et al., U.S. Pat. No. 2,288,226. Preferred onium compounds include the quaternary ammonium slats, a wise variety of such sensitizers being known in the art. Bis-quaternary ammonium salt sensitizing agents are more generally utilized, with the bis pyridinium salts wherein the pyridine nucleus is linked together by a divalent radical having at least 7 carbon atoms being particularly useful. Suitable quaternary ammonium salts are disclosed in Carroll U.S. Pat. No. 2,271,623, issued Feb. 3, 1942; Trivelli et al. U.S. Pat. No. 2,419,975, issued May 6, 1947; Piper U.S. Pat. No. 2,886,437, issued May 12, 1959; Beavers et al. U.S. Pat. No. 2,940,851, issued June 14, 1960; Beavers et al., U.S. Pat. No. 2,940,855, issued June 14, 1960; Beavers et al. U.S. Pat. No. 2,944,898, issued July 12, 1960; Carroll et al. U.S. Pat. No. 2,944,900, issued July 12, 1960 Carroll et a1. U.S. Pat. No. 2,944,902, issued July 12, 1960; and others.

Typical quaternary ammonium salts include:

p-xylene bis(acetamido dimethyl ammonium perchlorate),

Llethylenehis (l,l-dimethylhydrazinium perchlorate),

l/l tetmmelhylcnchin perchlorate J,

l,o-hexamethylenebis perchlorate),

l-n-decyll l -dimethyl hydrazinium perchlorate,

lauryltriethyl ammonium perchlorate,

N-heptoxymethyl pyridinium perchlorate,

n-nonyl pyridinium perchlorate, and

n-decyl pyridinium perchlorate. Numerous other quaternary ammonium salts or other onium salts such as described in Carroll and Allen U.S. Pat. No. 2,288,226, issued June 30, 1942, known to those skilled in the art as photographic silver halide development modifiers, can be used in our invention.

In addition, suitable speed addenda may be chosen having recurring structural units of the formula:

(l,l -dimcthylhydrazinium (l,l-dimcthylhydrazinium an oxygen atom and a sulfur atom, at least one ofQ and Q containing one of said substituents; B represents a substituent taken from the group consisting of LIL, -ll-o-;

o o R, 0

Z represents a divalent organic substituent, preferably having from 1 to 12 carbon atoms, such as alkylene groups, branched alkylene groups, alkyleneoxy groups, polyalkyleneoxy groups, hydroxyalkylene groups, and unsaturated alkylene groups, for example ethylene, butylene, octylene, dodecylene, 2-methyl butylene, 2- hydroxy propylene, 3,6-dioxaoctamethylene, l-methyl propylene, 1,4-butylenel -yne, 3-oxapentamethylene, polyethylene glycolyl, and arylene groups; R R R and R each represent alkyl groups having from 1 to 3 carbon atoms, and R, and R taken together, or R and R taken together, represent the atoms needed to complete (with --N') a heterocyclic ring having the formula:

R R R and R each represent alkyl groups having I to 3 carbon atoms, or hydrogen atoms; d, e, f and w may be 0 or 1; x and y may be 0 or a positive integer from I to 6; n is a positive integer; and n(w+l) is greater than 5.

[A'] is an anion such as p-toluenesulfonate. perchlorate, chloride and the like.

The repeating elements Q and Q may be the same or different moieties, either regularly or randomly distributed along the polymer chain, but chosen specifically from members of the group coming within the limits of formula (la) above.

It has further been found that certain polymers encompassed by the above identified formula (1) are effective as speed addenda in silver halide emulsions containing incorporated color couplers. These polymers have recurring structural units of the formula:

(2) R Rm II III r- T .J

Ru 1: n

and

and Z represents a straight aliphatic chain of l to 7 carbon atoms in which one or more hydrogen atoms may be replaced by hydroxyl, halogen, alkyl groups having 1 to 3 carbon atoms, etc;

b. alkylene groups of l to 12 carbon atoms; and

c. polyalkylene oxide groups of 2 to 12 carbon atoms;

at least one of Q" or 0" being selected from the group (a) above; xx and yy are whole numbers from 1 to 6; n is a positive integer greater than 5; and R,,, R,,, R and R each represent an alkyl group of from I to 3 carbon atoms, and [A'] is an anion, such as p-toluenesulfonate, perchlorate, or the like.

Typical compounds embraced within the general formula (1) above include the following:

Poly[hexamethylene-2-hydroxytrimethylene dimethylammonium) p-toluenesulfonate)] Poly[3-oxapentamethylene-Z-hydroxytrimethylene bis(dimethylammonium p-toluenesulfonate)] Poly[3-oxapentamethylene trimethylene bis (dimethylammonium p-toluenesulf0nate)] bis(- Poly[3,6-dioxaoctamethylene trimethylene bis (dimethylammonium p-toluenesulfonate)] Poly[3,6-dioxaoctamethylene-2- hydroxytrimethylene bis (dimethylammonium p-toluenesulfon ate) Poly[tetramethylene-2-hydroxytrimethylene bis (dimethylammonium p-toluenesulfonate)] Poly[3,8-dioxa-4,7-dioxodecamethylene hexamethylene bis (dimethylammonium p-toluenesulfonate)] Poly 3 ,8-dioxa-4,7-dioxodecamethylene tetramethylene bis (dimethylammonium p-toluenesulfonate)] Poly[ 3 ,8-dioxa-4,7-dioxodecamethylene 3,6- dioxaoctamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[p-cyclohexanedimethylene-Z- hydroxytrimethylene bis (dimethylammonium bis(- uenesulfonate)] Poly[polyethylene glycol (600) 2- hydroxytrimethylene bis (dimethylammonium p-toluenesulfonate)] Poly[polyethylene glycol (600) trimethylene bis(- dimethylammonium p-toluenesulfonate)] Poly (3,6-dioxaoctamethylene dimethylammoniump-toluenesulfonate) Poly (3,6-dioxaoctamethylene morpholinium-p-toluenesulfonate) P0ly[3,8-diaza-4,7-dioxodecamethylene-3,6-

dioxaoctamethylene bis(dimethylammonium p-toluenesulfonate)} In the above listing, polyethylene glycol (600) refers to a commercially available water soluble liquid polymer having a freezing point of -25C and a specific gravity of 1.13.

A number of compounds embraced by the general formula (2) above which increase the effective speed of silver halide emulsions containing dye-forming coupling agents are listed below:

Poly[5,10-dioxo-4, l l-diazatetradecamethylene-3,6-

dioxaoctamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[ 3 ,6-dioxaoctamethylene-4,7-dioxo-3 ,8-diaza decamethylene bis(dimethylammonium p-tolyenesulfonate)] Poly[5,8-dioxo-4,9-diazadodecamethylene-3- oxapentamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[6,7-dihydroxy-5,8-dioxo-4,9-

diazadodecamethylene 3,6-dioxaoctamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[3,6,9-trioxaundecamethylene-5,l0-dioxo-4,1 1-

diazatetra-decamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[3,8-dioxa-4,7-dioxodecamethylene-3,6-

dioxaoxtamethylene bis(dimethylammonium p-toluenesulfonate)] Poly[hexamethylene-S,8-dioxo-4,9-

diazadodecamethylene bis (dimethylammonium p-toluenesulfonateH The quantity of onium compound which is most advantageously employed varies with the nature of the specific onium compound and with the nature of the emulsion. Ordinarily, the most advantageous concentration has been found to be between about 50 mgs. and 8,000 mgs. of the onium compound per gram mole of silver halide in the emulsion, although greater or smaller concentrations can be employed. The optimum range of concentration for any onium compound described herein is ordinarily fairly narrow and can best be determined by employing a series of concentrations of the compound separately in several batches of the same emulsion and determining the sensitivity of the several batches before and after incorporation of the compound, in the usual manner which is, of course, well known to those skilled in the art.

As previously indicated, the antifoggant combination of this invention has been found effective in silver halide emulsions sensitized by other compounds which have in the past been found to give a good speed increase but have done so at the cost of high fog levels. For example, speed addenda which may be used in place of onium salts include polyalkylene glycols, and polythioethers. Exemplary of such compounds are polyalkylene glycols such as disclosed in Carroll et al., US. Pat. No. 2,716,062, issued Aug. 23, 1965; and Reynolds et al., US. Pat. No. 2,756,147, issued July 24, 1956. lonic polyalkylene oxide salts such as those disclosed in Carroll et al., US. Pat. No. 2,944,902, issued July 12, 1960 are also suitable.

The alkylene oxide derivatives used to sensitize the emulsions can be illustrated by the following specific examples, although our invention is in no way limited to the use of these specific compounds.

HOCH CH O(CH CH O) CH CH OH Polyethylene oxide HOCH Cl-l O(CH CH O),,CH CH OC, H

Polyethylene oxide oleylether wherein n is an integer from 7 to 200 or more.

Suitable thioethers which may be used in accordance with the present invention include those disclosed in Dann et al., US. Pat. No. 3,046,134, granted July 24, 1962. The polymeric compounds useful in the invention contain their sulfur atoms in the form of thioether linkages. By thioether linkage, I mean a linkage wherein the sulfur atom is a divalent atom which is joined to two non-oxocarbonylic carbon atoms. Moreover, the polymeric compounds are linear polymeric materials wherein the ether-sulfur atoms are present in the polymeric chain, as contrasted with polymeric materials containing their sulfur atoms as substituents attached to carbon atoms of the chain or as parts of a cross-linked arrangement. The polymeric materials used should have sufficient dispersibility in water (or a dilute alkaline solution), or an organic solvent such as acetone, the lower alcohols, 1,4-dioxane, ethyl acetate, etc. (directly, or in a colloid mill, or by other means, such as by a dispersing agent, e.g. sodium laurylsulfate, etc.), so that a sensitizing amount of the polymeric materials can be adsorbed by or associated with the silver halide grains.

The linear polymers containing a plurality of ethersulfur atoms in the chain can be represented by the following general formula:

wherein R represents an aliphatic linkage, such as an alkylene group, etc., and n represents a positive integer of at least about 3, i.e., the polymeric compounds comprise products obtained by condensations or addition-polymerizations involving at least about 3 molecules of reactants. in general, the polymeric materials have a molecular weight of at least about 250, although polymeric materials having molecular weight from about 500 to 10,000 have been found to be useful. The terminal groups of the polymers are generally hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups (or salts thereof, e.g., sodium potassium, etc.) or combinations of these.

The linear polymers represented by Formula (3) above comprise a well-known class of polymeric materials. Exemplary of such thioether polymers are those represented by the following formulae:

wherein R,, R R and R each represents alkylene containing from 2 to 20 carbon atoms; R represents hydrogen or lower alkyl; R represents alkylene containing from I to 6 carbon atoms; R, and R each represent a member selected from the class consisting of hydrogen, lower alkyl, and monocyclic aryl of the benzene series; R represents hydrogen or lower alkyl; X and X, each represents a member selected from the class consisting of oxygen, sulfur, amino, carbamyl, amido, carbonyl, oxycarbonyloxy, oxycarbonyl and carbonyloxy, provided that X does not represent oxycarbonyl when X, represents carbonyloxy, and provided X does not represent amido when X, represents carbamyl; X represents oxygen or sulfur; Z represents a member selected from the class consisting of:

wherein Z, represents alkylene containing from 2 to 20 carbon atoms;

--R,,; D. m and p each represents a positive integer of from 1 to 5 and n represents a positive integer of at least 3; said polymer having a molecular weight of at least about 250.

The antifoggant combination found effective to control fog in emulsions containing such sensitizing addenda comprises two members selected from known classes of antifoggants. Azaindene compounds useful for this purpose are disclosed in Carroll et al., U.S. Pat. No. 2,716,062; Allen et al. U.S. Pat. No. 2,735,769, granted Feb. 21, 1956; Allen et al., U.S. Pat. No. 2,743,181, granted Apr. 24, 1956; Tinker et al., U.S. Pat. No. 2,835,581, granted May 20, 1958; Reynolds U.S. Pat. No. 2,756,147, granted July 24, 1956; Carroll et al., U.S. Pat. No. 2,743,180, granted Apr. 24, 1956; and Zeitschrift fur Wiss. Phot. 47, 2-28 (1952). Such azaindenes are generally used in quantities of from 0.1 to 10 grams per mole of silver halide. Suitable azaindenes include, among others;

4-hydroxy-6-methyl-1,3 ,3a,7-tetrazaindene 5-carboxy-4-hydroxyl ,3 ,3a7-tetrazaindene 4-hydroxy-2-hydroxymethyl-6-methyl- 1,3,3a7tetrazaindene 2-chloromethyl-4-hydroxy-6-methyl-1,3,3a,7-

tetrazaindene 4-hydroxy-2-hydroxymethyl-6-phenyl-1,3,3a,7-

tetrazaindene 5-ethyl-4-hydroxy-2-hydroxymethyl-6-methyl- 1,3,3a,7-tetrazaindene and 2-chloromethyl-4-hydroxy-6-phenyl-l ,3 ,3a7-

tetrazaindene. Particularly suitable are 4-hydroxy-tetrazaindenes.

The vinyl sulfate polymer antifoggants useful in the present invention are described in King ct al, U.S. Pat. No. 3,347,486, issued Apr. 8, 1969. One class of such antifogging agents consists of salts of synthetic polyvinyl resins that comprise a monobasically sulfated bound monomeric unit recurring in the vinyl polymer chain. The monobasically sulfated bound vinyl monomeric unit may consitite from about 5 to mole percent of the total monomer units in the polymer. An especially preferred antifogging agent of this class is the ammonium salt of monobasically sulfated polyvinyl alcohol, which may also be called copoly(vinyl alcohol, vinyl hydrogen sulfate) ammonium salt.

Although the molecular weight of the polymers employed in our invention may be varied over a considerable range, it has been found that polymers prepared from commercial low molecular weight poly(vinyl alcohol) are highly advantageous. Similarly, the concentration of the polymer in silver halide emulsions may be varied over a considerable range to provide fog stability. Concentrations in the range from 1 to 75 grams of polymer per mole of Ag have previously been found to produce an antifoggant effect. It has been found that the greatest antifoggant effect is achieved according to this invention when the two antifoggant compounds employed are present in an approximate ratio of 1:1, although more or less of either may be employed if so desired.

The preferred polymers of this invention are copoly- (vinyl alcohol, vinyl hydrogen sulfate) salts, which may also be referred to as partially monobasically sulfated polyvinyl alcohol salts, but other monobasically sul- 9 l fated vinyl copolymers are also useful. The most useful ther contains a member of the specified classes of monobasically sulfated vinyl polymers are those which speed addenda, or in a layer contiguous thereto. contain about to 75 mole percent of the monobasi- The preparation of photographic emulsions and elecally sulfated monomer; particularly good results are aments in accordance with the practice of this invention chieved with polymers having to 50 mole percent 5 is exemplified in Examples 1 through 12. monobasically sulfated monomer. The salt forming The following compounds are added to separate porsubstituent advantageously is ammonium or alkali tions of a large grained bromoiodide black-and-white metal, although any salt forming group may be used negative emulsions (unless otherwise indicated) in the which does not interfere with the photographic emulamounts shown in the tables. The emulsions are coated sion in which the polymer is incorporated. 10 on cellulose acetate support at a coverage of 459 mg of Exemplary copolymers include poly(vinyl alcohol, silver and 1,040 mg of gelatin per square foot. A saminyl hydrogensulfate) ammonium salt; copoly(vinyl ple of each film coating is exposed for 1/25 second on alcohol, vinyl hydrogen sulfate, vinyl Z-hydroxy-S- an Eastman 1B sensitometer, processed for 5 minutes sulfophenyl carbonate) sodium salt; the mixed amin Kodak DK-SO Developer, fixed, washed and dried, monium-sodium salt of monobasically sulfated poly(N- in each case. B-hydroxyethyl-acrylamide); and the mixed ammoni- For the sake of convenience, results of these examum-sodium salt of monobasically sulfated poly [aples are presented in tabular form, employing the foly y y ethyl 'y llowing designations for. the addenda employed:

The preparation of silver halide emulsions involves three separate operations: (1) the emulsification and SPEED ADDENDA digestion or ripening of the silver halide, (2) the freeing of the emulsion from aqueous soluble salts, usually by S1 Terpolymer 0f bis(N,N-dimethylaminopropylwashing, and (3) the second digestion or after-ripening )adipamidetriethylene glycol ditosylate-1,4- to obtain increased sensitivity (Mees, The Theory of benzene diethanol, wherein x:y:z 5:4:1

CH3 on, {cmcmocmcmocmcm} r I oH:)aNH0o cH,)i00NH cHl)?1 I y din 2c7H7so3 C HJ, cHlcm-@-cmcm the Photographic Process, 1942, Page 3). The fog in- 5;, As above polymer wherein xzyzz 4:31] hibiting agents can be added at any stage, preferably S As above polymer wherein xzyzz 221:1

after the final digestion. Various silver salts may be S4 poly(thiodiethylene gmtame) used as a sensitive salt, such as silver bromide, silver iodide, silver chloride, or mixed silver halides such as sili: ,:L ver chlorobromide or silver bromoiodide. The sensitizi 0 L ing and stabilizing combinations of this invention are effective in the presence or absence of spectrally sensi- S Copoly[(2,2'-thi0diethyl) (benzene-1,4- tizing dyes. Since spectral sensitization may affect stadimethyl) glutarate] bility of emulsions with respect to sensitivity fog and S Copoly(ester-ether-sulfide), wherein p 3; latent image changes, the action of the compounds of w:x:y:z 3:l:2:2 this invention is not completely independent of spectral O O sensitization or other emulsion variables. It has been r ll CH g lomcmscmcml found, however, that both spectrally unsensitized emull gr 7 L sions and emulsions spectrally sensitized with cyanine O or merocyanme dyes, or both, can be treated according 0 0 f H I to this invention. (O T|3GH2)2 cm) o-o L O o 0 The emulsions, and elements comprising such emulsions, may be prepared in accordance with the teachq ings of Product Licensing Index, Vol. 92, December TCHICHQOCHZCHQJ 1971, publication 9232, pages 107-110, paragraphs I, n, VII, VIII, IX, x, XI, xn, xvn, XVIII, XIX, xxn, 1 As above, wherein p 2 and XXIII. The antifogging combination of this inven- 8 tion may be incorporated to advantage during manu- -DiaZa-6,l5-di0X0eicosane-l,20- facture in silver halide emulsions representing the vari- (py ni Perchlorate) ations described above. Moreover, fog control in binderless silver halide films prepared by vapor deposition of silver halide on a suitable support can be achieved by coating the antifogging agents of the invention over the vapor deposited silver halide, in a layer which fur- 3,779,769 1 1 12 S 7,18-Diaza-6,l9-dioxotetracosane-l,24-bis EXAMPLE 1 (pyridinium perchlorate) N(CH2)5CONH(CH2)1DNHC0( l) C10. Excellent photographic stability is obtained by the 5 use of a combination of 4-hydroxy-6-methyl-l,3,3a,7-

tetrazaindene (A,) and copoly(vinyl alcohol-vinyl ammonium sulfate) (A in a silver halide emulsion conlO taining a ter-polymer of bis(N,N-dimethylaminopropyll83,6,9,12,15,l8,21,24-oclohexacosane- )adipamide-triethylene glycol ditosylatel ,4-benzene bis(pyridinium Perchlorate) diethanol in the ratio of 5:4:1 (S

The indicated compounds are added to separate portions of a large grained bromoiodide black-and-white negative emulsion, in the amounts shown in the table. The emulsions are coated on cellulose acetate support S Oleic ether of polyethylene glycol at a coverage of 459 mg of silver and 1040 mg of gela- C, H O (C H O) H tin per square foot. A sample of each film coating is ex- ANTIFOGGANTS posed on an Eastman 1B sensitometer, processed for 5 minutes in a black-and-white developer, fixed, washed, A sodium salt of 4-hydroxy-6-methyl-l,3,3a,7- and dried tetrazaindene l0 N- cmcHionomcm-N 2010i Table l illustrates that when the antifoggants are added separately to a large grained bromoiodide black- I i and-white emulsion containing the polyquaternary NN Na speed addendum the fog is not controlled. When the same antifoggants are used in combination, large speed OH gains and excellent fog stabilization are obtained. For A Copoly(vinyl alcohol-vinyl ammonium sulexample, in Table I approximately a threefold speed infate) crease is obtained while holding the 0.22 fresh fog to 0.27 after 2 weeks incubation at 120F/50 percent relative humidity. in addition, there is no desensitization i. H osomfli/y upon incubation.

TABLE I [Large grained bromoiodide black-ancl-white emulsion] Fresh 2 wks. at 120 F./50% RH Addenda (g./m. Ag.) Rel Rel.

Coating S1 Ai A: speed Fog speed 7 Fog After 1 week incubation at120 F./50% RH.

wherein y 6L7 mole percent EXAMPLE 2 3|85 carboxy 4 hydroxy 2 methy| 1,3,3a7 The same combination of antifoggants is used in a tetrazaindene large grained bromoiodide negative speed color emulsion containing the same polyquaternary speed adden- N N CH! dum and processed in Eastman Color Negative and Eastman Color Print developers. The results in Table Hoock ll show that fog stabilization is obtained along with an excellent increase in contrast. For the color tests of Table ll, the compounds are 55 added to separate portions of a red-sensitive sulfur and A Poly[2-hydroxy isopropylacrylate -partially gold-sensitized gelatino silver bromoiodide emulsion sulfated], ammonium-sodium salt containing a dispersion of a cyan-forming phenolic coupler of the type described in U.S. Pat. No. 2,474,29- [(CH;-Cint-(CH,CH),-(CH,-CH)-)ln 3. The emulsion samples and a control are coated on :0 :0 0:0 cellulose acetate film support at 100 mg Ag and 272 mg l gelatin per square foot. A sample of each film coating CHCH, A HCH lS exposed on an Eastman 1B sensitometer and processed 1n the Eastman Color Negative Process or the R: 1 CH1 Eastman Color Print Process (12 minute developon cisoiNa (isomm ment).

Fog

Fresh 1 wks. at 120 F./50% Rll Rel. Fog speed Coating Eastman color negaprocess:

EXAMPLE 5 Fresh 2 wire. at 120 F./50 RH Rel. Rel. speed Fog speed Fog w n Fe Since fog stabilization might be attributed to a pH effect of the copoly(vinyl alcohol-vinyl ammonium sulfate), this is investigated. Table V shows the results of the addition of various salts of the above polymer at 40 controlled pH values and the measurement of surface Table IV illustrates that this thioether polymer (S pH of the emulsion after coating, drying and keeping. may be used at higher concentrations, resulting in sub The P difi'erences are negligible; therefore, the stantial speed increases, while fog is controlled in the foggant effect is not due to a pH change resulting from presence of the antifoggants A, and A the addition of the polymer.

TABLE v [Large grained bromoiodide black-and-whlte emulsion] Fresh 2 wks. at 120 F./50% RH Rel. Rel. speed 7 Fog speed Fresh 2 wks. at 120 F./50% itH Rel. Y Fog speed Addenda (g./m. 5g.)

S1 A1 A:

TABLE III [Large grained bromoiodide bleck-end-white emulsion] TABLE IV Rel speed EXAMPLE 3 Table III illustrates the effectiveness of the same anti- 20 foggant concentration with a large grained bromoio- EXAMPLE 4 Addenda (g-l Addenda (gJm. ag.)

Coating dide black-and-white emulsion employing poly(thiodiethylene glutarate) as the speed addendum, prepared and tested as set forth in Example 1.

Coating III-Control Coating 3 3, p 3 3, pH=6.60 (Na Measurement of the surface pH is taken after the coated emulsion has been kept at room temperature for several weeks.

EXAMPLE 6 Table VI shows results similar to those seen in Table I, utilizing polymeric quaternary salt addenda containing different ratios of monomers than that employed in Example 1.

TABLE VI EXAMPLE 8 This example demonstrates that another tetrazaindene, 5-carboxy-4-hydroxy-2-methyll ,3 ,3a,7-

[Large grained bromoiodide black'and-white emulsion] After 1 week incubation at 120 F./50% RH.

EXAMPLE 7 This example shows that increased photographic sensitivity results when a higher concentration of a polymeric quaternary salt is used, and that the increased photographic stability is due to the combination of copoly(vinyl alcoholvinylammonium sulfate) and the tetrazaindene (A can be substituted for the sodium salt of 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene to achieve approximately the same degree of photographic sensitivity and stability.

The same procedure as outlined in Example 7 is followed. Table Vlll contains the sensitometric data.

TABLE VIII Addenda (g./m.ag.) Fresh 2 wks. at 120 F./50% RII Re]. Re].

Coating S1 A1 A; A: speed 7 Dmin Dm, speed 7 Dana Du."

VIII-Control 100 1.57 0.18 2.45 0. 72 1.10 2.22

VIII-A 3.0 3.0 300 1.10 0.46 2.06 0.50 0.64 0.81

VIII-B 3.0 3.0 282 1.25 0.38 2.11 0.12 1.82 1.05

VIII-C 3.0 3.0 3.0 232 1.52 0.27 2.22 209 1.00 0.66 2.14

sodium salt of 4-hydroxy-6-methyl-l,3,3a,7- EXAMPLE 9 tetrazaindene. The addenda are added separately and in combination to a large grained bromoiodide blackand-white emulsion and coated as described in Exam- This example demonstrates that there are other P 1 (Table A Sample of Each coating is exposed p0ly(thioether) type compounds which can be used as an Eastman lB sensitometer, processed for 5 minutes in an alternate to the polymeric quaternary salt in combi- Eastman Kodak Developer DK-SO, fixed, washed and nation with the azaindene and vinyl sulfate copolymer. dried. Table V lists the sensitometric data obtained The testing, exposing and processing procedures are from both fresh and incubated (2wks. at l20F/50% the same as indicated in Example 7 and the sensitomet- RH) samples. ric data are reported in Table lX.

TABLE VII Fresh 2 wks. at 120 F. RH Addenda (g./m. ag.)

Rel Rel.

Coating S 1 A1 A 2 speed Fog speed 'Y Fog TABLE IX Addenda (pa/m. 11g.) Fresh '1 wks. m. 12H lR/MrZ, ltli ltrl. Ill-l. uHllllK X (30110. M A1 N|)I(!(l 1 F014 .qu-ed 7 Fm:

lX--( 0ntr0l 1.38 0. H 32. 5 0. X7 0. 7H l,\'- 3.0 3.0 3.0 2'24 1.38 0.21 lllll I. ll] 0.2.) lX- (i. U 3. 0 3. O 204 l. 37 0. l'.l .540 l. 43 (l. 23 LY 3. 0 3. O 3. O 234 11 25 O. 20 182 1. l3 0. 4! l 3. 0 3. 0 3. 0 219 1.10 0. ll! llll l. l'. 0. 42

EXAMPLE This example demonstrates that simple organic quaternary salts may be used as an alternate to the polymeric quaternary salts. The testing, exposing and pro- A. poly(vinyl alcohol, vinyl hydrogen sulfate);

B. poly(vinyl alcohol, vinyl hydrogen sulfate, vinyl 2-hydroxy-5-sulfophenyl carbonate);

C. poly(N-B-hydroxyethyl acrylamide); and

c essing procedures are the same as indicated in Exam- 5 D. poly(2-hydroxy isopropyl acrylate) [an azainple 7, and the sensitometric data are reported in Table dene]. X. 2. In a photographic emulsion as set forth in claim 1,

TABLE X 2 wks. at 120 F./50% Fresh RlI Addenda (g./m./ag.)

Rel. Rel Coating X Cone. A1 A: speed 7 Fog speed 7 Fog X-Control 1 100 1. 52 0.15 13. 5 o. 70 1. 41 x A $1 229 1.47 0.111 209 1. 25 0. 37

182 1. 3a 0. 14s 0. us 0. 68

EXAMPLE l l the improvement wherein said vinyl copolymer is se- This example demonstrates that polyglycols (e.g., lected from the g p consisting of p y( y alcohol,

S may be used as an alternate to polymeric quaternary salt. The testing, exposing and processing procedures are the same as indicated in Example 7 except that the incubations are for only one week at vinyl hydrogen sulfate), ammonium salt; copoly(vinyl alcohol, vinyl hydrogen sulfate, vinyl 2-hydroxy-5- sulfophenyl carbonate), sodium salt; and the mixed ar'nmonium-sodium salt of monobasically sulfated 120F/ 50% RH instead of two weeks at the same condipoly[a(hydroxymethyl)ethyl acrylate].

tions. The sensitometric data are reported in Table XI.

3. ln a photographic emulsion as set forth in claim 1,

TABLE XI Fresh 1 wk. at 120 F./% RH Addenda (g./m./ag-) Rel. Rel. Coating S11 A1 A: speed 7 Fog speed 7 Fog XI-Control 100 1. 43 0. 20 80 1. 19 0. 39 X] A 1. 0O H 159 l. 08 0. 21 100 0. 92 O. 54 1. 00 3. 0 170 1. 23 0. 22 209 1. 22 0. 24 1. 00 a. 0 151 1. 22 0.18 145 1. 20 0. 31 1. 00 3.0 3. 0 186 1.17 0.20 214 1. 32 (1. 22

EXAMPLE 12 the improvement wherein said vinyl copolymer is copo This example demonstrates that other compounds containing the sulfate group may be used'as an alternate to the copoly(vinyl alcohol-vinylammonium sulfate) antifoggant. The testing, exposing and processing procedures are the same as indicated in Example 7, and sensitometric data are reported in Table XII.

ly(vinyl alcohol-vinyl ammonium sulfate).

4. In a photographic emulsion as set forth in claim 1, the improvement wherein said vinyl copolymer is the ammonium-sodium salt of partially sulfated poly[2- hydroxy isopropyl acrylate].

5. In a photographic emulsion as set forth in claim 1,

TABLE Xll Fresh 2 wks. at l20F/50% RH Addenda (g/rn Ag.) Rel. Coating S1 A. A4 Speed Fog Speed y Fog Xll- Control 100 1.56 0.17 52 0.96 0.70 Xll,4 3.0 3.0 3.0 251 1.60 .21 240 L42 .4]

The invention has been described in detail with particular reference to preferred embodiments thereof, but it sill be understood that variations and modifications can be effected within the spirit and scope of the invention.

I claim:

1. In a fog-stabilized photographic emulsion comprising silver halide grains sensitized with a speedincreasing concentration of an onium compound, an alkylene oxide polymer, or a thioether polymer, the improvement wherein said emulsion is stabilized against fog by an antifoggant combination comprising a 4- hydroxy tetrazaindene and a monobasically sulfated vinyl copolymer selected from the group consisting of salts of C. poly(N-B-hydroxyethyl acrylamide); and

D. poly(2-hydroxy isopropyl acrylate); further comprising a speed-sensitizing concentration of a composition selected from the group consisting of onium compounds, alkylene oxide polymers, and thioether polymers.

8. The photographic element of claim 7, wherein said vinyl copolymer is copoly(vinyl alcohol-vinyl ammonium sulfate).

9. The photographic element of claim 7, wherein said azaindene is the sodium salt of 4hydroxy-6-methyll,3,3a,7-tetrazaindene.

10. A photographic element comprising a support having coated thereon at least one silver halide emulsion layer, said element containing a fog-stabilizing amount of an antifoggant combination comprising a 4- hydroxytetrazaindene and a monobasically sulfated vinyl copolymer selected from the group consisting of salts of A. poly(vinyl alcohol, vinyl hydrogen sulfate);

B. poly(vinyl alcohol, vinyl hydrogen sulfate, vinyl Z-hydroxy-S-sulfophenyl carbonate); C. poly(N-B-hydroxyethyl acrylamide); and D. poly(2-hydroxy isopropyl acrylate); and a speedsensitizing concentration of a quaternary ammonium salt.

11. The photographic element of claim 10, wherein said vinyl copolymer is copoly(vinyl alcohol-vinyl ammonium sulfate).

12. The emulsion of claim 1 wherein the 4-hydroxytetrazaindene is present in a concentration of from 0.1 gram to 10 grams per mole of silver halide and the monobasically sulfated vinyl copolymer is present in a concentration of from 1 to grams of polymer per mole of silver.

13. The emulsion of claim 1 wherein the 4-hydroxytetrazaindene and the monobasically sulfated vinyl copolymer are present in a ratio of about 1:1.

14. The element of claim 7 wherein the 4-hydroxytetrazaindene is present in a concentration of from 0.1 gram to 10 grams per mole of silver halide and the monobasically sulfated vinyl copolymer is present in a concentration of from 1 to 75 grams of polymer per mole of silver.

15. The element of claim 7 wherein the 4-hydroxytetrazaindene and the monobasically sulfated vinyl copolymer are present in a ratio of about 121.

k t k 

2. In a photographic emulsion as set forth in claim 1, the improvement wherein said vinyl copolymer is selected from the group consisting of poly(vinyl alcohol, vinyl hydrogen sulfate), ammonium salt; copoly(vinyl alcohol, vinyl hydrogen sulfate, vinyl 2-hydroxy-5-sulfophenyl carbonate), sodium salt; and the mixed ammonium-sodium salt of monobasically sulfated poly( Alpha (hydroxymethyl)ethyl acrylate).
 3. In a photographic emulsion as set forth in claim 1, the improvement wherein said vinyl copolymer is copoly(vinyl alcohol-vinyl ammonium sulfate).
 4. In a photographic emulsion as set forth in claim 1, the improvement wherein said vinyl copolymer is the ammonium-sodium salt of partially sulfated poly(2-hydroxy isopropyl acrylate).
 5. In a photographic emulsion as set forth in claim 1, the improvement wherein said azaindene is the sodium salt of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene.
 6. In a photographic emulsion as set forth in claim 1, the improvement wherein said azaindene is 5-carboxy-4-hydroxy-2-methyl-1,3,3a,7-tetrazaindene.
 7. A photographic element comprising a support having coated thereon at least one silver halide emulsion layer, said element containing a fog-stabilizing amount of an antifoggant combination comprising a 4-hydroxytetrazaindene and a monobasically sulfated vinyl copolymer selected from the group consisting of salts of A. poly(vinyl alcohol, vinyl hydrogen sulfate); B. poly(vinyl alcohol, vinyl hydrogen sulfate, vinyl 2-hydroxy-5-sulfophenyl carbonate); C. poly(N- Beta -hydroxyethyl acrylamide); and D. poly(2-hydroxy isopropyl acrylate); further comprising a speed-sensitizing concentration of a composition selected from the group consisting of onium compounds, alkylene oxide polymers, and thioether polymers.
 8. The photographic element of claim 7, wherein said vinyl copolymer is copoly(vinyl alcohol-vinyl ammonium sulfate).
 9. The photographic element of claim 7, wherein said azaindene is the sodium salt of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaIndene.
 10. A photographic element comprising a support having coated thereon at least one silver halide emulsion layer, said element containing a fog-stabilizing amount of an antifoggant combination comprising a 4-hydroxytetrazaindene and a monobasically sulfated vinyl copolymer selected from the group consisting of salts of A. poly(vinyl alcohol, vinyl hydrogen sulfate); B. poly(vinyl alcohol, vinyl hydrogen sulfate, vinyl 2-hydroxy-5-sulfophenyl carbonate); C. poly(N- Beta -hydroxyethyl acrylamide); and D. poly(2-hydroxy isopropyl acrylate); and a speed-sensitizing concentration of a quaternary ammonium salt.
 11. The photographic element of claim 10, wherein said vinyl copolymer is copoly(vinyl alcohol-vinyl ammonium sulfate).
 12. The emulsion of claim 1 wherein the 4-hydroxy-tetrazaindene is present in a concentration of from 0.1 gram to 10 grams per mole of silver halide and the monobasically sulfated vinyl copolymer is present in a concentration of from 1 to 75 grams of polymer per mole of silver.
 13. The emulsion of claim 1 wherein the 4-hydroxy-tetrazaindene and the monobasically sulfated vinyl copolymer are present in a ratio of about 1:1.
 14. The element of claim 7 wherein the 4-hydroxy-tetrazaindene is present in a concentration of from 0.1 gram to 10 grams per mole of silver halide and the monobasically sulfated vinyl copolymer is present in a concentration of from 1 to 75 grams of polymer per mole of silver.
 15. The element of claim 7 wherein the 4-hydroxy-tetrazaindene and the monobasically sulfated vinyl copolymer are present in a ratio of about 1:1. 